1. Field of the Invention
The present invention relates to an alpine ski boot having a rigid shell whose shell base is surmounted with an upper that is at least partially journalled on the latter about a transverse axis, the upper comprising at least one front portion and one rear portion or rear spoiler, in the open position to enable passage of the foot, a closure assembly for the upper forming a collar on the lower part of the leg, comprising a tightening system at least partially encircling the upper in order to be tensioned by a tensioning lever fixed on one of the component parts of the upper, the flexion control means of amplitude of movement and magnitude of force flexion in the frontward direction being located on a rear portion of the upper.
2. Description of Background and Relevant Information
Various solutions have already been proposed in order to obtain such flexion control means.
Particularly, European Patent Application No. 350,023 describes a ski boot whose shell base comprises an extension constituting two symmetrical portions separated by an indent at the rear defining two lips, whereas in the front portion, the extension is constituted by two plates that intersect by overlapping.
Such a boot is especially adapted for insertion of the foot from above and includes an anti-rocking means towards the rear obtained in the form of an abutment, arranged at the upper portion of the heel.
The adjustment of the front flexion, both of amplitude and force, is in fact accomplished by modifying the position of a cursor between the two lips of the rear indent, the cursor being adjustable in translation by means provided with screws.
The control and adjustment device for front flexion here is arranged on an element, in fact the rear extension of the shell base, obtained by molding in an integral piece, from a single material. It thus becomes necessary to choose a material that has, simultaneously, both the resistance qualities required by the shell base, as well as the relative elasticity required by the extension of the shell base. It therefore becomes difficult, due to these reasons, to find an ideal compromise to obtain a shell whose base is comfortable and whose upper portion is elastically reliable.
Moreover, such a technique also leads to demolding difficulties, that are basically due to the height of the extensions and to the overlapping to be obtained in the front portion.
Also, this type of boot, because of this construction, is difficult to put on because its entire upper portion must be removed in order to introduce the foot, even more so because the collar is blocked in its front-to-rear position as explained above.
In order to remedy this lack of rear opening in the boot, a Swiss Patent No. 375,526 is also known, which discloses an alpine ski boot with rear entry of the foot and in which the angular bottoming of the rear spoiler, one of the component elements of the upper, is limited in the frontward direction by a retention element that is built to project at the lower portion of the rear spoiler, and cooperates with an edge of the heel on the shell base.
It is easy to understand that such means for limiting flexion would not be exact because they only limit overall flexion, and do not provide any specific control for frontward movements.